CN114951994B - Laser constant-temperature welding control system and method - Google Patents
Laser constant-temperature welding control system and method Download PDFInfo
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- CN114951994B CN114951994B CN202210583494.5A CN202210583494A CN114951994B CN 114951994 B CN114951994 B CN 114951994B CN 202210583494 A CN202210583494 A CN 202210583494A CN 114951994 B CN114951994 B CN 114951994B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/20—Bonding
- B23K26/21—Bonding by welding
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/70—Auxiliary operations or equipment
- B23K26/702—Auxiliary equipment
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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Abstract
The invention discloses a laser constant temperature welding control system and a method, which utilize infrared light reflected by a welding point along an original light path to judge whether the temperature of welding point solder exceeds the standard or not; judging whether welding flux of the welding point is in a burning state or not by utilizing visible light of a leakage beam of the laser transmitter after the visible light emitted by the welding point returns along an original light path; and judging whether the solder is in a set liquefaction state by utilizing the output laser emitted by the laser emitter to reach the welding point and then return along the original light path and the leaked light beam after passing through the laser emitter. The invention simplifies the requirements of lens coating in the prior art, reduces the application of spectroscopes and increases the working distance of a laser focusing head; the invention does not need to install a separate paraxial reflection laser detector, reduces the dependence and cost on equipment, and solves the fire risk problems caused by control overshoot, error, loop oscillation and the like possibly generated by a temperature regulator in the prior art.
Description
Technical Field
The invention belongs to the technical field of constant-temperature laser soft solder welding, and particularly relates to a laser constant-temperature welding control system and method.
Background
Laser brazing is a brazing technique in which laser is used as a heat source to heat and melt brazing filler metal, and laser brazing filler metal welding is divided into soft brazing filler metal and hard brazing filler metal welding. Solder has a liquidus temperature lower than 450 ℃ and is called soldering, and is mainly used for connecting electronic components of a printed circuit board. The laser radiation is used to heat the lead wire of the integrated circuit, and the heat is transferred to the substrate through soldering flux or preset solder. When the temperature reaches the soldering temperature, the soldering flux and the solder melt, and the substrate and the lead are wetted to form a connection. The laser soft soldering integrated circuit adopts YAG laser emitter, semiconductor optical fiber coupling laser emitter and low-power optical fiber laser emitter.
Constant temperature laser soldering technology is generally designed around an infrared temperature sensor, all of which adopt non-contact temperature measurement and control laser output power through similar PID, neural network or automatic feedback adjustment thereof. When the temperature of the welding spot is higher than a set value, automatically reducing the laser power; and when the temperature of the welding spot is lower than the set value, the laser power is automatically increased. Such constant temperature welding has in principle a number of significant drawbacks. First, there is a large difference between the measured temperature and the actual temperature in the non-contact infrared thermometry, the difference depending on the emissivity of the measured material. Emissivity is the ability of an object being measured to emit infrared energy, which is characteristic of the temperature of the object. Color, composition, liquid or solid state, surface structure, etc. will greatly affect emissivity. There is a substantial change in emissivity during the solid to liquid conversion process during soldering. The emissivity of solid solder is typically significantly higher than that of liquid solder, and therefore the infrared energy emission capability of liquid solder decreases, and the measured temperature also follows the decrease. At the moment, the laser power is dynamically increased under the action of a feedback control loop to compensate the apparent temperature drop; and the actual temperature of the liquid solder may have reached the ignition point after it has been irradiated with the higher energy laser. In addition, the welding out-of-control stage after reaching the ignition point can generate visible light to flash fire, the infrared emission wavelength can enter the near infrared section, and the real temperature of the welding spot can not be accurately measured due to the fact that the infrared emission wavelength is likely to exceed the measuring range of the infrared temperature sensor.
In patent CN201711364680.5, a method and a system for controlling the safety of laser welding based on infrared temperature measurement and variable emissivity are adopted, wherein the method can dynamically adjust the emissivity according to the solder state to ensure accurate temperature measurement. However, this approach still suffers from several drawbacks in practice. The three sensors required in the original method are a visible light sensor, an infrared temperature sensor and a laser sensor respectively, wherein the visible light sensor, the infrared temperature sensor and the welding laser separate reflected laser and temperature infrared energy from the reflected laser through two spectroscopes. However, the original scheme has the following problems: firstly, the two spectroscopes are found to be too complex in wavelength composition to be transmitted and reflected, so that the two spectroscopes cannot be produced, or only the transmittance of working laser can be preferentially considered, and the two spectroscopes have very large attenuation on other wavelengths such as infrared light, visible light and the like; at the same time, the two reflectors need to reduce the actual working distance of the laser focusing head, and if the designed working distance is increased, the focal diameter may become larger, so that a small workpiece cannot be welded. Secondly, the reflective laser sensor adopts a paraxial arrangement, and the sensor needs to be exactly aligned with the laser focus when in implementation, but the actual operation is very difficult; and thirdly, in the control system of the original scheme, after the measured temperature is acquired, the laser transmitter is driven after calculation is carried out only through the PID automatic control unit, and when the PID generates overshoot due to the self parameters, higher laser power is output, and then the feedback loop is waited for reducing the laser power again to reduce the welding temperature, at least a plurality of control calculation periods are needed. During this time, due to the abnormal rise of temperature, the welding material is likely to have spontaneous combustion, and even if the laser power is reduced, combustion continues to generate great potential safety hazards; fourth, the emissivity of the infrared temperature sensor adopted in the original scheme must be adjustable, but there are few devices which can meet the requirements in the actual market, so the purchasing of the devices is greatly limited.
Disclosure of Invention
In order to solve the temperature problem, the invention provides a laser constant-temperature welding system and a laser constant-temperature welding method, which can reduce implementation difficulty and provide safety.
The invention discloses a laser constant temperature welding system for realizing one of the purposes, which comprises a solder liquefaction detection control unit, a solder combustion detection control unit and a solder overtemperature detection control unit;
the welding flux liquefaction detection control unit is used for detecting the light intensity value of a light beam which is returned along an original light path after output laser of the laser emitter reaches a welding point and is leaked after passing through the laser emitter in the laser welding process, comparing the light intensity value with a set welding flux liquefaction threshold value, judging whether the welding flux is liquefied or not, selecting different set temperature values according to the light intensity value of reflected light of the welding flux of the current welding point, obtaining a temperature regulation value according to the set temperature value and the temperature value of the current welding point, and receiving the temperature regulation value by the laser driver and outputting a control signal to regulate the light power of the output laser of the laser emitter;
the welding flux combustion detection control unit is used for detecting the light intensity value of a light beam leaked after the visible light of a welding point of a welded object passes through the laser transmitter along an original light path in the laser welding process, comparing the light intensity value with a set welding flux combustion threshold value, judging whether welding flux is combusted or not, and controlling the on-off of the working of the laser transmitter through the laser driver;
the solder overtemperature detection control unit is used for obtaining the temperature of the solder of the welding point according to the infrared light in the reflected light of the welding point of the welded object in the laser welding process, comparing the temperature with a solder safety threshold, judging whether the temperature of the welding point exceeds the safety threshold, and controlling the on-off of the work of the laser transmitter through the laser driver.
Further, the laser driver comprises three input ports, wherein two input ends are independent emission stopping interfaces, and the output end of the laser driver module can be independently controlled to stop supplying power to the laser emitter.
Further, the solder liquefaction detection control unit includes:
the reflected light sensor is used for detecting the light intensity value of the leakage light beam after the reflected light of the welding point solder passes through the laser emitter;
the selector is used for receiving the output signal of the reflected light sensor, comparing the output signal with a set solder liquefaction threshold value and outputting different set temperature values according to the compared result;
and the temperature regulator is used for outputting a temperature regulating value according to the set temperature value output by the selector and the temperature value of the welding point solder measured by the infrared temperature sensor, receiving the temperature regulating value by an input signal end of the laser driver and regulating the optical power of the output laser of the laser transmitter according to the input temperature regulating value.
Still further, be provided with first light filter and first spectroscope on the light path of reflection light sensor, first spectroscope sets up in laser emitter's optical axis light leak end for carry out the beam split to the light beam that leaks through laser emitter, first light filter is band-pass filter for the reflected light of the output laser of follow laser emitter that separates out from the light beam through laser emitter's optical axis light leak end.
The center wavelength of the passband of the reflected light of the output laser of the laser emitter is equal to the center wavelength of the output laser of the laser emitter, and the passband width of the passband is within a set range.
Further, the solder burn detection control unit includes:
the visible light sensor is used for detecting the light intensity value of the leakage light beam after the visible light emitted by the welding point solder passes through the laser emitter in the laser welding process;
the first comparator is used for receiving the output signal of the visible light sensor, comparing the output signal with a set solder burning threshold value, and outputting a control signal according to the compared result, wherein the control signal is output to a first emission stopping interface of the laser driver, and the first emission stopping interface of the laser driver is used for controlling the on-off of the work of the laser emitter.
Still further, be provided with second light filter and first spectroscope on visible light sensor's the light path, first spectroscope sets up in laser emitter's optical axis light leak end for carry out the beam split to the light beam that leaks through laser emitter, the second light filter is band-pass filter, is used for separating visible light from the light that passes through laser emitter's optical axis light leak end.
Further, the solder overtemperature detection control unit includes:
the infrared temperature sensor is used for measuring the temperature of welding point solder in the laser welding process and outputting a temperature signal;
the second comparator is used for receiving the output temperature signal of the infrared temperature sensor, comparing the output temperature signal with a set solder safety threshold value, and outputting a control signal according to the compared result, wherein the control signal is output to a second emission stopping interface of the laser driver, and the second emission stopping interface of the laser driver is used for controlling the on-off of the work of the laser emitter.
Further, a second beam splitter is arranged on the optical path of the infrared temperature sensor, and the second beam splitter is arranged on the optical path of the welding point and the laser gathering head and is used for separating infrared light from reflected light of the welding point.
Compared with the prior art that the temperature of the welding spot is controlled through the PID operation unit or the temperature regulator, the temperature control module directly judges through the temperature of the welding spot, the control period is also reduced, and the risk that the temperature of the welding spot cannot be timely regulated because the PID operation unit or the temperature regulator is out of control is avoided.
The second purpose of the invention is achieved by a laser constant temperature welding control method, which comprises the following steps:
in the laser welding process, infrared light reflected by a welding point is utilized to judge whether the temperature of the welding point solder exceeds a safety threshold value; judging whether welding point solder is in a burning state or not by utilizing a beam which is returned along an original light path after output laser of a laser transmitter reaches a welding point and is leaked after passing through the laser transmitter; judging whether the welding point solder is in a set liquefaction state or not by utilizing the visible light emitted by the welding point solder during combustion and passing through the light beam leaked by the laser emitter along the original light path;
stopping the laser transmitter when the welding point solder is in a burning state or the temperature of the solder exceeds a safety threshold value; when the welding point solder is in a non-liquefied state, increasing the power of the laser transmitter to increase the temperature of the welding point; when the welding point solder is in a liquefied state, the temperature regulator is used for keeping the temperature of the welding point at the temperature when the solder is in a set liquefied state by comparing the temperature of the welding point measured by the infrared temperature sensor and the temperature obtained by measuring the light beam which returns along an original light path after the output laser of the laser transmitter reaches the welding point and is leaked after passing through the laser transmitter.
The set liquidized state refers to a state when the solder is in a completely liquidized state.
Further, the method for judging liquefaction of the welding point comprises the following steps:
the output laser of the laser transmitter is reflected by the solder after reaching the welding point, the reflected laser returns along the original light path, and after being leaked by the laser transmitter, the reflected laser sequentially passes through the spectroscope and the optical filter and then enters the reflected light sensor, and the reflected light sensor measures the input light to obtain the light intensity value O 1 The method comprises the steps of carrying out a first treatment on the surface of the The infrared temperature sensor measures infrared light separated by the second beam splitter to obtain a temperature value T;
when the light intensity value O 1 When the solder liquidation threshold value is smaller than the solder liquidation threshold value, judging that the solder is not liquidized, and selecting a calibration value T by a selector 1 As a set temperature input value of the thermostat;
when the light intensity value O 1 When the temperature is larger than the solder liquefaction threshold, judging that the solder is liquefied, and selecting a calibration value T by a selector 2 As a set temperature input value of the thermostat;
the temperature value T is used as a measured temperature input value of the temperature regulator;
the temperature regulator calculates a temperature control value according to the set temperature input value and the measured temperature input value, and the signal input end of the laser driver receives the temperature control value and outputs a control signal to regulate the output light power of the laser emitter according to the temperature control value.
The measured temperature input value of the final temperature regulator is equal to the set temperature input value;
further, the calibration value T 1 Below the nominal value T 2 ；
Further, the calibration value T 2 The calibration process of (2) is as follows:
heating the solder of the welding point, and when the temperature of the solder reaches a preset temperature, obtaining a calibration value T by using the temperature value of the solder measured by the infrared temperature sensor 2 The method comprises the steps of carrying out a first treatment on the surface of the The temperature at which the solder reaches the preset temperature is the actual temperature of the solder measured using the contact sensor.
The preset temperature is a true temperature of the solder in a state where the solder is completely liquefied.
The calculation method of the optical power of the output laser of the laser transmitter is controlled by the laser driving module according to the calculation of the set temperature input value and the measured temperature input value.
The beneficial effects are that:
(1) Compared with the method that a plurality of spectroscopes are added on the light path between the laser focusing head and the welding point to judge whether the welding flux of the welding point is liquefied or burnt in the prior art, in the scheme, only one spectroscope is needed on the light path of the laser focusing head and the welding point to reflect infrared light for temperature measurement, working lasers with other wavelengths and visible light are transmitted along the original light path, and judgment on whether the welding flux of the welding point is liquefied or burnt can be realized through one spectroscope and two optical filters arranged at the light leakage end of the optical axis of the laser transmitter in the laser, so that the requirement of the lens coating of the spectroscopes in the prior art is greatly simplified, the spectroscopes in the scheme are easy to produce, and the occupation of the actual working distance of the laser focusing head is less;
(2) In the prior art, the reflection laser sensor generally belongs to paraxial installation, and has the problem of difficult alignment with a laser welding point, and the scheme judges whether the solder is liquefied or not by measuring the change of the light beam returned along an original light path and leaked after passing through the laser transmitter, so that an independent paraxial detector is not needed, the problem of alignment between the sensor and the laser welding point is avoided, and the dependence on equipment and the cost are reduced;
(3) According to the invention, whether the welding point burns or not is judged by measuring the leakage beam of visible light after passing through the laser transmitter, and an additional spectroscope is not required to be added in front of the focusing head, so that the dependence on equipment and the cost are reduced;
(4) In the prior art, whether the welding point burns or not is judged through the temperature output signal of the infrared temperature sensor after passing through the temperature controller, but the temperature controller possibly generates fire risks caused by control overshoot, errors, loop oscillation and the like.
Drawings
FIG. 1 is a schematic diagram of an embodiment of the present invention;
fig. 2 is a simplified schematic of the weld reflected laser path.
Detailed Description
The following detailed description is presented to explain the claimed invention and to enable those skilled in the art to understand the claimed invention. The scope of the invention is not limited to the following specific embodiments. It is also within the scope of the invention to include the claims of the present invention as made by those skilled in the art, rather than the following detailed description.
One embodiment of the system of the present invention is described below in conjunction with fig. 1 and 2.
The system comprises three detection light paths, which respectively correspond to a solder liquefaction detection control unit, a solder combustion detection control unit and a solder overtemperature detection control unit;
a detection light path of the solder liquefaction detection control unit: the optical system comprises a first spectroscope 103, a first optical filter 102 and a reflective optical sensor 101 which are sequentially arranged along an optical path; the output laser of the laser transmitter sequentially passes through the laser focusing head and the second beam splitter and then reaches the welding point; after the laser reflected by the welding point returns through the original light path, the light beam leaked by the laser transmitter reaches the reflective optical sensor 101 through the first spectroscope 103 and the first optical filter 102, and the reflective optical sensor 101 detects the light intensity value of the input light.
A detection light path of the solder combustion detection control unit: the optical system comprises a first spectroscope 103, a second optical filter 109 and a visible light sensor 108 which are sequentially arranged along an optical path; the visible light emitted by the welding point reaches the visible light sensor 108 along the original light path through the first spectroscope 103 and the second optical filter 109, and the visible light sensor 108 detects the light intensity value of the input light;
and a detection light path of the solder overtemperature detection control unit: comprises a second beam splitter 115 and an infrared temperature sensor 114 which are arranged in sequence along the light path; the output laser of the laser transmitter sequentially passes through the laser focusing head and the second beam splitter and then reaches the welding point; the laser reflected by the welding point returns through the original light path and then reaches the infrared temperature sensor 114 through the second beam splitter; the infrared temperature sensor 114 outputs a temperature value of the welding point according to a light intensity value of the input light;
the solder liquefaction detection control unit further comprises a control part, wherein the control part comprises a selector 116, a temperature regulator 118 and a laser driver 112, and the selector 116 selects different temperature values as set temperature input values of the temperature regulator 118 according to the light intensity value output by the reflection light sensor compared with a preset solder liquefaction value;
the temperature regulator 118 calculates and controls an output signal of the laser driver 112 based on the set temperature value input from the selector 116 and the input temperature value of the infrared temperature sensor 114, the output signal of the laser driver 112 being used to control the optical power of the output laser of the laser emitter.
The laser comprises a pump source 105, a first laser cavity mirror 104 and a second laser cavity mirror 106; one end of the first laser cavity mirror 104 is connected with the pump source 105, and the other end is connected with the first spectroscope 103; one end of the second laser cavity mirror 106 is connected with the pump source 105, and the other end is connected with the laser focusing head 107; the first laser cavity mirror 104 and the second laser cavity mirror 106 may be independent optical lenses or integrated devices with the same function
The first laser cavity mirror 104 is a total reflection mirror, and theoretically, the first laser cavity mirror 104 can perform total reflection on the injected laser, but the actual reflectivity is less than 100%, so that a part of weak laser enters the second beam splitter 115 of the second beam splitter module through the first laser cavity mirror; the second laser cavity mirror 106 is an output mirror, and the second laser cavity mirror 106 partially reflects the incident laser light, and the other part of the laser light passes through the second laser cavity mirror and enters the laser focusing mirror 107 of the laser focusing module.
The solder burning detection control unit further comprises a control part, the control part comprises a first comparator 111, an output signal end of the first comparator 111 is connected with a first emission stopping input end of the laser driver 112, the first comparator 111 compares a light intensity value output by the visible light sensor 108 with a preset solder burning threshold value, and when the light intensity value is greater than or equal to the preset solder burning threshold value, the first emission stopping input end of the laser driver receives a laser emission stopping signal of the first comparator 111, and the laser driver controls the laser emitter to stop outputting laser; and when the light intensity value is reduced below a preset solder burning threshold value, the laser driver controls the laser emitter to recover the laser output.
The solder overtemperature detection control unit further comprises a control part, the control part comprises a second comparator 113, an output signal end of the second comparator 113 is connected with a second emission stopping input end of the laser driver 112, the second comparator 113 compares a temperature value output by an infrared temperature sensor 114 with a preset solder safety threshold value, when the temperature value is larger than the preset solder safety threshold value, a second emission stopping input end of the laser driver receives a laser emission stopping signal of the second comparator 113, and the laser driver controls the laser emitter to stop outputting laser; the preset solder safety threshold is a safety temperature measured by the infrared sensor 114 when the solder temperature is greater than the melting point and less than the ignition point, and the specific value is determined according to actual requirements; and when the temperature value is reduced below a preset solder safety threshold, the laser driver controls the laser emitter to recover the laser output.
The laser driver 112 is a general or special laser driving power supply; it may adjust the emitted optical power of the laser transmitter by an analog or digital signal.
One embodiment of the method of the present invention is described below.
The first laser cavity mirror 104, the pump source 105 and the second laser cavity mirror 106 together form a laser emitter light source, wherein the first laser cavity mirror 104 is theoretically totally reflecting for laser light, the second laser cavity mirror 106 is theoretically partially reflecting for laser light, the laser light is output to the laser focusing head 107 through the second laser cavity mirror 106, the laser light emitted by the laser focusing head 107 is focused to a welding point position through the second beam splitter 115, and when the laser light irradiates on the welding point, part of the laser light is necessarily reflected back into the laser focusing head 107 according to the principle of reversibility of an optical path.
Since the actual reflectivity of the first laser cavity mirror 104 cannot reach 100%, the still weak light beam can pass through the first laser cavity mirror 104 into the beam splitter 1. Based on this principle, after the laser light reflected from the welding point passes through the laser focusing head 107, the reflected laser light and visible light may also enter the first beam splitter 103 through the laser emitter light source. As shown in fig. 2.
The first spectroscope 103 splits the light beam leaked through the first laser cavity mirror 104 into two paths, one path enters the reflective light sensor 101 after passing through the first optical filter 102, and the other path enters the visible light sensor 108 after passing through the second optical filter 109.
The first filter 102 in the present invention is a bandpass filter, which can block light with a selected wavelength and other wavelengths, and its passband center wavelength is equal to the center wavelength of the laser output by the laser transmitter and passband width is ±20nm. Its function is to retain reflected laser light and to remove stray light of other wavelengths.
The second filter 109 of the present invention is a bandpass filter that passes selected wavelengths, other wavelengths, and has a passband that is no greater than the photosensitive wavelength range of the visible light sensor 108. Its function is to remove the reflected laser light and keep the visible light passing through.
The reflected light sensor 101 is used to measure the minute laser power leaked through the first laser cavity mirror 104. The laser light reflected by the laser irradiated on the welding point further passes through the second laser cavity mirror 106, the pump source 105, the first laser cavity mirror 104, the first spectroscope 103 and the first optical filter 102, and then enters the reflective optical sensor 101. When the solder reaches the melting temperature, the material becomes liquid, the reflectivity of the working laser is greatly increased, and the reflective optical sensor 101 outputs the detected light intensity value of the reflective laser to the input end of the selector 116;
when the intensity value of the reflected laser is smaller than the preset solder liquefying value, indicating that the solder is not liquefied, the selector 116 selects the calibrated value T in the first storage 110 1 As a set temperature input value of the temperature regulator 118, a calibration value T in the first memory 110 1 Setting a temperature value corresponding to the melting point of the solder, and liquefying the solder;
when the intensity value of the reflected laser light is greater than a preset solder liquefying value, indicating that the solder has been liquefied, the selector 116 selects the calibrated value T in the second memory 117 2 As a set temperature input value of the temperature regulator 118, the second memory 117 storesCalibration value T 2 The temperature measured by the infrared temperature sensor when the solder is completely liquefied is set to be the temperature preset by the solder.
The calibration value T stored in the first memory 110 1 Below the nominal value T stored in the second memory 117 2 The method comprises the steps of carrying out a first treatment on the surface of the The output of the temperature regulator 118 is connected to the laser driver 112, and the laser driver 112 provides energy to the laser pump source.
The visible light sensor 108 is used to measure visible light leaking through the first laser cavity mirror 104; visible light will be generated when the temperature of the weld spot increases abnormally to the ignition point. The visible light passes through the second beam splitter 115, the laser focusing head 107, the second laser cavity mirror 106, the pump source 105, the first laser cavity mirror 104, the first beam splitter 103, and the second optical filter 109, and then enters the visible light sensor 108. The first comparator 111 receives the output signal of the visible light sensor 108, a preset solder burning detection threshold B is stored in the first comparator 111, and when the input value of the first comparator 111 is greater than the preset solder burning detection threshold B, the output signal end of the first comparator 111 outputs a control signal to control the laser driver 112 to stop the output of the laser driver immediately so as to achieve the purpose of stopping laser.
The infrared light emitted by the welding point enters the infrared temperature sensor 114 after passing through the second beam splitter 115, the second comparator 113 receives the temperature signal measured by the infrared temperature sensor 114, the second comparator 113 compares the measured temperature value of the infrared temperature sensor 114 with a set safety temperature threshold, and when the measured temperature value of the infrared temperature sensor 114 is higher than the set safety temperature threshold, the output signal end of the second comparator 113 outputs a control signal to control the laser driver 112 to immediately stop supplying power to the pump source 105. The safe temperature threshold is a set protection value, the safe temperature threshold is a temperature value which is larger than the solder liquefying threshold but smaller than the solder burning threshold, and if the constant temperature welding cannot stabilize the temperature, the laser output is stopped immediately when the temperature is continuously increased to exceed the set temperature value.
The reflective optical sensor 101 in the present invention is a device for converting visible or invisible light into an optical intensity electrical signal, and its photosensitive wavelength range is not less than 800-1200nm, and its specific implementation and output value have no influence on the method in the present invention.
The visible light sensor 108 is a device for converting visible light or invisible light into light intensity electric signals, the sensitive wavelength range of the visible light sensor is not less than 450-800nm, and the specific implementation mode and the output value have no influence on the method.
The first laser cavity mirror 104, the pump source 105 and the second laser cavity mirror 106 are key devices for forming a laser transmitter. The laser transmitter refers to a laser transmitting unit consisting of three devices, and the laser center wavelength output by the laser transmitter is within 800-1200 nm.
The first beam splitter 103 is a device for splitting a beam of light into two beams, and the splitting ratio and implementation manner of the first beam splitter have no influence on the method described in the present invention. The spectral ratio only affects the power of the actual laser output of the measured signal intensities of the subsequent reflected light sensor 101 and the visible light sensor 108, and when the spectral ratio becomes larger, the signal received by the photoelectric sensor becomes stronger, and the same function can still be achieved by changing the preset judgment threshold values in the first comparator 111 and the selectors-116.
The temperature regulator 118 of the present invention is a negative feedback automatic regulator. It has two input ports, one of which is a set temperature input port, connected to the selector 116; the other input is a measured temperature input, which is connected to an infrared temperature sensor 114; the infrared temperature sensor 114 is a temperature value output by the infrared temperature sensor, this measured temperature value being used as a feedback input to the thermostat 118; and the output of the laser power control device is also connected with a laser driver 112, and the actual laser power is automatically adjusted by a closed loop system consisting of the laser driver 112, a laser emitter, a laser focusing head 107, a second beam splitter 115 and infrared temperature sensors-114. The input temperature setting and measured temperature input of thermostat-118 will gradually tend to be equal under its control.
The laser driver 112 according to the present invention is a general-purpose or special-purpose laser driving power supply that can adjust laser emission power (intensity) by analog or digital signals, and has a separate emission stop interface connected to the first comparator 111 and the second comparator 113, respectively. The laser emission may be terminated immediately after receiving the emission stop signal of the first comparator 111 or the second comparator 113; when the input signal of the comparator 116 or the second comparator 113 is lower than the judgment value, the laser driver automatically resumes the laser emission.
What is not described in detail in this specification is prior art known to those skilled in the art.
Claims (10)
1. The laser constant temperature welding control system is characterized by comprising a solder liquefaction detection control unit, a solder combustion detection control unit and a solder overtemperature detection control unit;
the welding flux liquefaction detection control unit is used for detecting the light intensity value of a light beam which is returned along an original light path after output laser of the laser emitter reaches a welding point and is leaked after passing through the laser emitter in the laser welding process, comparing the light intensity value with a set welding flux liquefaction threshold value, judging whether the welding flux is liquefied or not, selecting different set temperature values according to the light intensity value of reflected light of the welding flux of the current welding point, obtaining a temperature regulation value according to the set temperature value and the temperature value of the current welding point, and receiving the temperature regulation value by the laser driver and outputting a control signal to regulate the light power of the output laser of the laser emitter;
the welding flux combustion detection control unit is used for detecting the light intensity value of a light beam leaked after the visible light of a welding point of a welded object passes through the laser transmitter along an original light path in the laser welding process, comparing the light intensity value with a set welding flux combustion threshold value, judging whether welding flux is combusted or not, and controlling the on-off of the working of the laser transmitter through the laser driver;
the solder overtemperature detection control unit is used for obtaining the temperature of the solder of the welding point according to the infrared light in the reflected light of the welding point of the welded object in the laser welding process, comparing the temperature with a solder safety threshold, judging whether the temperature of the welding point exceeds the safety threshold, and controlling the on-off of the work of the laser transmitter through the laser driver.
2. The laser constant temperature welding control system according to claim 1, wherein the solder liquefaction detection control unit includes:
the reflected light sensor is used for detecting the light intensity value of the leakage light beam after the reflected light of the welding point solder passes through the laser emitter;
the selector is used for receiving the output signal of the reflected light sensor, comparing the output signal with a set solder liquefying threshold value and outputting different set temperature values according to the compared result;
and the temperature regulator is used for outputting a temperature regulating value according to the set temperature value output by the selector and the temperature value of the welding point solder measured by the infrared temperature sensor, receiving the temperature regulating value by an input signal end of the laser driver and regulating the optical power of the output laser of the laser transmitter according to the input temperature regulating value.
3. The laser constant temperature welding control system according to claim 2, wherein the optical path of the reflective optical sensor is provided with a first optical filter and a first spectroscope, the first spectroscope is disposed at an optical axis light leakage end of the laser transmitter and is used for splitting a light beam leaked by the laser transmitter, and the first optical filter is a band-pass filter and is used for separating reflected light of output laser of the laser transmitter from the light beam leaked by the optical axis light leakage end of the laser transmitter.
4. The laser constant temperature welding control system according to claim 1, wherein the solder burn detection control unit includes:
the visible light sensor is used for detecting the light intensity value of the leakage light beam after the visible light emitted by the welding point solder passes through the laser emitter in the laser welding process;
the first comparator is used for receiving the output signal of the visible light sensor, comparing the output signal with a set solder burning threshold value, and outputting a control signal according to the compared result to control the on-off of the work of the laser transmitter.
5. The laser constant temperature welding control system according to claim 4, wherein a second filter and a first spectroscope are disposed on an optical path of the visible light sensor, the first spectroscope is disposed at an optical axis light leakage end of the laser transmitter and is used for splitting a light beam leaked by the laser transmitter, and the second filter is a band-pass filter and is used for separating visible light from light passing through the optical axis light leakage end of the laser transmitter.
6. The laser constant temperature soldering control system according to claim 1, wherein the solder overtemperature detection control unit includes:
the infrared temperature sensor is used for measuring the temperature of welding point solder in the laser welding process and outputting a temperature signal;
and the second comparator is used for receiving the output temperature signal of the infrared temperature sensor, comparing the output temperature signal with a set solder safety threshold value, and outputting a control signal according to the compared result to control the on-off of the work of the laser transmitter.
7. The laser constant temperature welding control system according to claim 6, wherein a second beam splitter is disposed on the optical path of the infrared temperature sensor, and the second beam splitter is disposed on the optical path of the welding point and the laser condensing head, for separating infrared light from reflected light of the welding point.
8. A laser constant temperature welding control method of the system of claim 2, wherein:
in the laser welding process, infrared light reflected by a welding point is utilized to judge whether the temperature of the welding point solder exceeds a safety threshold value; judging whether the welding point solder is in a set liquefaction state by utilizing a beam which is returned along an original light path after the output laser of the laser transmitter reaches the welding point and leaks after passing through the laser transmitter; judging whether the welding point solder is in a burning state or not by utilizing the visible light emitted when the welding point solder burns and passing through the light beam leaked by the laser emitter along the original light path;
stopping the laser transmitter when the welding point solder is in a burning state or the temperature of the solder exceeds a safety threshold value; when the welding point solder is in a non-liquefied state, increasing the power of the laser transmitter to increase the temperature of the welding point; when the welding point solder is in a liquefied state, the temperature regulator is used for keeping the temperature of the welding point at the temperature when the solder is in a set liquefied state by comparing the temperature of the welding point measured by the infrared temperature sensor and the temperature obtained by measuring the light beam which returns along an original light path after the output laser of the laser transmitter reaches the welding point and is leaked after passing through the laser transmitter.
9. The laser constant temperature welding control method according to claim 8, wherein the method of judging that the welding point solder is in a liquefied state comprises:
the output laser of the laser transmitter is reflected by the solder after reaching the welding point, the reflected laser returns along the original light path, and after leaking through the laser transmitter, the laser enters a reflected light sensor, and the reflected light sensor measures the input light to obtain a light intensity value O 1 The method comprises the steps of carrying out a first treatment on the surface of the The infrared temperature sensor measures infrared light separated by the second beam splitter to obtain a temperature value T;
when the light intensity value O 1 When the solder liquidation threshold value is smaller than the solder liquidation threshold value, judging that the solder is not liquidized, and selecting a calibration value T by a selector 1 As a set temperature input value of the thermostat;
when the light intensity value O 1 When the temperature is larger than the solder liquefaction threshold, judging that the solder is liquefied, and selecting a calibration value T by a selector 2 As a set temperature input value of the thermostat;
the temperature value T is used as a measured temperature input value of the temperature regulator;
the temperature regulator calculates a temperature control value according to the set temperature input value and the measured temperature input value, the signal input end of the laser driver receives the temperature control value and outputs a control signal according to the temperature control value to regulate the output light power of the laser emitter;
the second beam splitter is arranged on the optical paths of the welding point and the laser gathering head and is used for separating infrared light from reflected light of the welding point.
10. The laser constant temperature welding control method according to claim 9, wherein the calibration value T 2 The calibration process of (2) is as follows:
heating the solder of the welding point, and when the temperature of the solder reaches a preset temperature, obtaining a calibration value T by using the temperature value of the solder measured by the infrared temperature sensor 2 。
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE795286A (en) * | 1972-02-18 | 1973-08-13 | Glaverbel | METHOD AND DEVICE FOR APPLYING AN ADHERENT WELDING ALLOY LAYER |
| CA1138260A (en) * | 1980-10-30 | 1982-12-28 | Real Gravel | Solder feeding gun and attachment |
| US5662643A (en) * | 1994-09-28 | 1997-09-02 | Abiomed R & D, Inc. | Laser welding system |
| KR20090050531A (en) * | 2007-11-16 | 2009-05-20 | 재단법인 포항산업과학연구원 | Laser brazing device and method thereof |
| EP2373147A1 (en) * | 2010-03-30 | 2011-10-05 | Fujitsu Limited | Repair apparatus and method for electronic component and heat-transfer cap |
| CN105171173A (en) * | 2015-09-23 | 2015-12-23 | 深圳市智立方自动化设备有限公司 | Laser solder-ball-jetting soldering equipment |
| CN108311767A (en) * | 2017-12-18 | 2018-07-24 | 武汉凌云光电科技有限责任公司 | A kind of method and system of the laser welding security control based on infrared measurement of temperature variable emissivity |
| JP6744686B1 (en) * | 2019-09-26 | 2020-08-19 | オー・エム・シー株式会社 | Laser soldering method and device |
-
2022
- 2022-05-25 CN CN202210583494.5A patent/CN114951994B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE795286A (en) * | 1972-02-18 | 1973-08-13 | Glaverbel | METHOD AND DEVICE FOR APPLYING AN ADHERENT WELDING ALLOY LAYER |
| CA1138260A (en) * | 1980-10-30 | 1982-12-28 | Real Gravel | Solder feeding gun and attachment |
| US5662643A (en) * | 1994-09-28 | 1997-09-02 | Abiomed R & D, Inc. | Laser welding system |
| KR20090050531A (en) * | 2007-11-16 | 2009-05-20 | 재단법인 포항산업과학연구원 | Laser brazing device and method thereof |
| EP2373147A1 (en) * | 2010-03-30 | 2011-10-05 | Fujitsu Limited | Repair apparatus and method for electronic component and heat-transfer cap |
| CN105171173A (en) * | 2015-09-23 | 2015-12-23 | 深圳市智立方自动化设备有限公司 | Laser solder-ball-jetting soldering equipment |
| CN108311767A (en) * | 2017-12-18 | 2018-07-24 | 武汉凌云光电科技有限责任公司 | A kind of method and system of the laser welding security control based on infrared measurement of temperature variable emissivity |
| JP6744686B1 (en) * | 2019-09-26 | 2020-08-19 | オー・エム・シー株式会社 | Laser soldering method and device |
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